Advanced Stages Of Diabetic Nephropathy Research Articles

Oral anserine supplementation does not attenuate type-2 diabetes or diabetic nephropathy in BTBR ob/ob mice.

Carnosine, a naturally occurring dipeptide present in an omnivorous diet, has been shown to ameliorate the development of metabolic syndrome, type-2 diabetes (T2D) and early- and advanced-stage diabetic nephropathy in different rodent models. Anserine, its methylated analogue, is more bio-available in humans upon supplementation without affecting its functionality. In this work, we investigated the effect of oral supplementation with anserine or carnosine on circulating and tissue anserine and carnosine levels and on the development of T2D and diabetic nephropathy in BTBR ob/ob mice. BTBR ob/ob mice were either supplemented with carnosine or anserine in drinking water (4mM) for 18weeks and compared with non-supplemented BTBR ob/ob and wild-type (WT) mice. Circulating and kidney, but not muscle, carnosine, and anserine levels were enhanced by supplementation with the respective dipeptides in ob/ob mice compared to non-treated ob/ob mice. The evolution of fasting blood glucose, insulin, fructosamine, triglycerides, and cholesterol was not affected by the supplementation regimens. The albumin/creatine ratio, glomerular hypertrophy, and mesangial matrix expansion were aggravated in ob/ob vs. WT mice, but not alleviated by supplementation. To conclude, long-term supplementation with anserine elevates circulating and kidney anserine levels in diabetic mice. However, anserine supplementation was not able to attenuate the development of T2D or diabetic nephropathy in BTBR ob/ob mice. Further research will have to elucidate whether anserine can attenuate milder forms of T2D or metabolic syndrome.

Gut microbiota profile and selected plasma metabolites in type 1 diabetes without and with stratification by albuminuria.

Abnormal gut microbiota and blood metabolome profiles have been reported both in children and adults with uncomplicated type 1 diabetes as well as in adults with type 1 diabetes and advanced stages of diabetic nephropathy. In this study we aimed to investigate the gut microbiota and a panel of targeted plasma metabolites in individuals with type 1 diabetes of long duration without and with different levels of albuminuria. In a cross-sectional study we included 161 individuals with type 1 diabetes and 50 healthy control individuals. Individuals with type 1 diabetes were categorised into three groups according to historically measured albuminuria: (1) normoalbuminuria (<3.39mg/mmol); (2) microalbuminuria (3.39-33.79mg/mmol); and (3) macroalbuminuria (≥33.90mg/mmol). From faecal samples, the gut microbiota composition at genus level was characterised by 16S rRNA gene amplicon sequencing and in plasma a targeted profile of 31 metabolites was analysed with ultra HPLC coupled to MS/MS. Study participants were aged 60 ± 11years (mean ± SD) and 42% were women. The individuals with type 1 diabetes had had diabetes for a mean of 42 ± 15years and had an eGFR of 75 ± 25mlmin-1 (1.73m)-2. Measures of the gut microbial beta diversity differed significantly between healthy controls and individuals with type 1 diabetes, either with micro- or macroalbuminuria. Taxonomic analyses showed that 79 of 324 genera differed in relative abundance between individuals with type 1 diabetes and healthy controls and ten genera differed significantly among the three albuminuria groups with type 1 diabetes. For the measured plasma metabolites, 11 of 31 metabolites differed significantly between individuals with type 1 diabetes and healthy controls. When individuals with type 1 diabetes were stratified by the level of albuminuria, individuals with macroalbuminuria had higher plasma concentrations of indoxyl sulphate and L-citrulline than those with normo- or microalbuminuria and higher plasma levels of homocitrulline and L-kynurenine compared with individuals with normoalbuminuria. Whereas plasma concentrations of tryptophan were lower in individuals with macroalbuminuria compared with those with normoalbuminuria. We demonstrate that individuals with type 1 diabetes of long duration are characterised by aberrant profiles of gut microbiota and plasma metabolites. Moreover, individuals with type 1 diabetes with initial stages of diabetic nephropathy show different gut microbiota and plasma metabolite profiles depending on the level of albuminuria. Graphical abstract.

Serum Klotho protein level in type 2 diabetic patients depending on the renal function

The study aimed to assess serum Klotho protein level in type 2 diabetic patients depending on kidney function.&#x0D; Methods. This observational study included 72 patients with diabetes mellitus (DM) and 26 patients with acute coronary syndrome. The control group consisted of 20 healthy subjects. Depending on the presence of albuminuria and glomerular filtration rate (GFR), the diabetics were divided into the following groups: group I included the patients with normal GFR and without albuminuria (n = 25); group ІІ consisted the patients with normal GFR and albuminuria (n = 23); group III – the patients with reduced GFR and albuminuria (n = 24) and group ІV included the patients with acute coronary syndrome (n = 26).&#x0D; The GFR was calculated using the CKD EPI formula (KDIGO 2012). The concentration of Klotho protein was determined by enzyme-linked immunosorbent assay.&#x0D; Results. The development of diabetic nephropathy in type 2 diabetic patients accompanied by a significant decrease of soluble Klotho compared with the controls and the patients of the1-st group. The level of Klotho protein in the group of patients with albuminuria decreased to (490.66 ± 58.76) pg/ml (p &lt;0.05). The lowest concentration of Klotho (443.58 ± 46.92) pg/ml was found in the advanced stages of diabetic nephropathy, namely in patients with albuminuria and impaired renal function. Moreover, a significantly decreased serum Klotho was observed in acute coronary syndrome group in comparison with the control group (p &lt;0.05). There were inverse correlations of Klotho concentration with urinary albumin and blood creatinine levels and a direct correlation between Klotho and GFR.&#x0D; Conclusions. The obtained data indicated the key role of Klotho protein in the formation of renal pathology in type 2 diabetes and the feasibility of practical use of Klotho determination as an early diagnostic marker of renal disorders and cardiovascular risk assessment. The strategies improving Klotho production may be useful in the reduction of both renal and vascular lesions progression in type 2 diabetic patients.

Targeting mammalian serine/threonine-protein kinase 4 through Yes-associated protein/TEA domain transcription factor-mediated epithelial-mesenchymal transition ameliorates diabetic nephropathy orchestrated renal fibrosis

RationaleTubulointerstitial fibrosis, which is closely related to functional injury of the kidney, can be observed in advanced stages of diabetic nephropathy (DN). Mammalian serine/threonine-protein kinase 4 (MST1), a core component of the Hippo pathway that is involved in cellular proliferation and differentiation, plays a crucial role in the pathogenesis of multiple metabolic diseases, kidney diseases and cancer. MethodsIn type 1 and type 2 diabetic animals, as well as in human proximal tubular epithelial cells (HK-2), activation of MST1 was analyzed by immunohistochemistry and western blotting. In db/db mice, MST1 protein was knocked down or overexpressed by shRNA, and renal function, fibrosis, and downstream signaling were then investigated. RNA silencing and overexpression were performed by using an MST1 or YAP knockdown/expression lentivirus to investigate the regulation of MST1-mediated YAP/TEAD signaling pathways in the fibrosis process in HK-2 cells. Luciferase and coimmunoprecipitation (co-IP) assays were used to identify whether YAP directly regulated TEAD activation by forming a YAP-TEAD heterodimer, which ultimately leads to tubulointerstitial fibrosis. ResultsMST1 activation was significantly decreased in type 1 and type 2 diabetic nephropathy. Notably, the downregulation of MST1 activation was also observed in HK-2 cells in a glucose- and time-dependent manner. In vivo, downregulation of MST1 was sufficient to promote renal dysfunction and fibrosis in db/m mice, whereas overexpression of MST1 ameliorated diabetic nephropathy-induced renal fibrosis. Further mechanistic study demonstrated that activated YAP induced by MST1 inhibition directly upregulated TEAD activation by binding to TEAD and forming a YAP-TEAD heterodimer, resulting in the promotion of epithelial-mesenchymal transition (EMT) and fibrosis in renal tubular epithelial. ConclusionsMST1 activation represents a potential therapeutic strategy to treat or prevent the progression of diabetic nephropathy-induced renal fibrosis.

Mitochondria-related reversal of early-stage diabetic nephropathy in donor kidney after transplantation in mice.

Renal diabetic changes are frequent in kidney transplantation (KTx) donors. Whether these diabetic changes are reversible remains a topic of debate. This study aimed to test the hypothesized reversibility of diabetic changes after KTx. C57BL/6J mice were randomly divided into three groups: the control group, early-stage group (ESG), and advanced-stage group (ASG). Diabetes mellitus (DM) was induced in mice by intraperitoneal injection of streptozotocin (STZ) at 50 mg/kg body weight for five consecutive days. Blood glucose levels ≥16.7 mmol/L were indicative of diabetic mice. The kidneys from ESG and ASG were transplanted to control mice 12 or 32 weeks after STZ injection. Kidney tissue, blood, and 24-hour urine specimens of donor and recipient mice were collected before KTx and 28 days after KTx, respectively. We measured the body weight, blood glucose, histological changes, reactive oxygen species (ROS), apoptosis. Electron microscopy was also performed to evaluate the mitochondrial morphology. The expression of NADPH oxidases (NOXs) was assessed by qRT-PCR. Kidneys from early-stage diabetic mice showed evidence of lesion reversal four weeks after KTx, including decreased urinary albumin and reversal of histological changes. Besides, mitochondrial swelling, oxidative stress, apoptosis, and overexpression of NOXs in the kidneys were also suppressed. Conversely, no changes were observed in kidneys from advanced-stage diabetic mice after KTx. We confirmed that early-stage but not advanced-stage diabetic nephropathy (DN) is reversible, which is related to reduced NOX expression and improvement in mitochondrial function. These results indicated that kidneys with early-stage DN could be used for KTx in clinical practice, as the disease may be reversed following KTx.

792-P: Effect of Oral Anserine Supplementation on Type 2 Diabetes and Diabetic Nephropathy in BTBR ob/ob Mice

Carnosine, a naturally occurring dipeptide present in an omnivorous diet, has been shown to ameliorate the development of metabolic syndrome, type 2 diabetes and early- and advanced-stage diabetic nephropathy (Albrecht et al. 2017) in different rodent models. The physiological mechanisms of the protection by carnosine is presumably related to its anti-lipidemic, anti-hyperglycemic and anti-glycation actions. As anserine, its methylated analogue, is more bio-available in humans upon supplementation (Everaert et al. 2018) without affecting its functionality, it was now aimed to investigate the effect of oral supplementation with anserine on the development of severe diabetes and advanced diabetic nephropathy in BTBR ob/ob mice. Male and female BTBR ob/ob mice were either supplemented with 4mM carnosine or anserine in drinking water for 18 weeks and compared with non-supplemented BTBR ob/ob and wt/wt mice. Tissue carnosine and anserine levels were determined with HPLC and metabolic markers were determined in clinical lab of University Hospital UZ Ghent. Gastrocnemius carnosine and anserine levels were lower in male ob/ob vs. wt/wt mice, but were not affected by supplementation. Kidney carnosine and anserine levels were not different between ob/ob and wt/wt mice, but anserine levels were significantly higher in anserine-treated mice compared to non-treated ob/ob mice. The evolution of fasting blood glucose, fructosamine, triglycerides and cholesterol was not affected by the supplementation regimen. The area of the glomerular tuft and whole glomerulus was bigger in ob/ob vs. wt/wt mice, but not affected by supplementation. Based on the currently measured markers, it is suggested that chronic oral anserine supplementation is not able to attenuate the development of diabetes or diabetic nephropathy in the severe model of BTBR ob/ob mice. Further research will have to elucidate whether anserine can attenuate milder forms of metabolic syndrome or type 2 diabetes. Disclosure I. Everaert: None. M. Hanssens: None. H.J. Baelde: None. W. Derave: None. Funding Research Foundation - Flanders

Retrospective Analysis of Bone Metabolism in Patients on Waiting List for Simultaneous Pancreas-Kidney Transplantation.

Posttransplant osteoporosis, which evolves from preexisting bone pathologies, represents a serious complication with deteriorating consequences. The aim of our study was to evaluate epidemiological data on bone mineral density (BMD) in subjects with type 1 diabetes (T1DM) in advanced stages of diabetic nephropathy indicated for simultaneous pancreas-kidney transplantation (SPK). We retrospectively compiled biochemical and densitometrical data from 177 patients with T1DM at CKD (chronic kidney disease) stages G4-G5 (115 men, 62 women, median age 40 yr, diabetes duration 23 yr) enrolled on waiting list for SPK for the first time between the years 2011 and 2016. Median Z-scores were as follows: lumbar spine (LS): -0.8 [interquartile range -1.75 to 0.1]; total hip (TH): -1.2 [-1.75 to -0.6]; femoral neck (FN): -1.2 [-1.9 to -0.7]; and distal radius (DR): -0.8 [-1.4 to -0.1]. We noted a gender difference in LS, with worse results for men (-1.1 vs. -0.3) even after adjusting for BMI (body mass index) and glomerular filtration (p < 0.001). Osteoporotic and osteopenic ranges (based on T-scores) for all major sites were 27.7% and 56.5%, respectively, with similar results across both genders. Women had a significantly higher proportion of normal BMD in LS than men (67.7 vs. 49.4%, p < 0.05). Patients with T1DM at CKD stages G4-G5 exhibited serious BMD impairment despite their young age. Men surprisingly displayed lower Z-scores and higher percentages of pathological BMD values in LS than women did. The introduction of adequate preventive measures during the advanced stages of diabetic nephropathy to prevent bone loss is recommended.

Two cases of advanced stage rapidly progressive diabetic nephropathy effectively treated with combination therapy including RAS blocker, GLP-1 receptor agonist and SGLT-2 inhibitor

We herein report two cases of advanced stage rapidly progressive diabetic nephropathy that were effectively treated with combination therapy including renin-angiotensin-aldosterone system (RAS) blocker [angiotensin II receptor blocker (ARB)], glucagon-like peptide-1 (GLP-1) receptor agonist and sodium glucose transporter-2 (SGLT-2) inhibitor. A 30-year-old woman with advanced stage diabetic nephropathy [estimated glomerular filtration rate (eGFR): 20.7mL/min/1.73m2; proteinuria: 13.2g/gCr], showing a rapidly progressive pattern (annual eGFR change: - 60.0mL/min/1.73m2/year), had improvement in proteinuria (5.9g/gCr) and eGFR change (+ 4.3mL/min/1.73m2 over 15 weeks) after administration of ARB (irbesartan 25mg/day), GLP-1 receptor agonist (liraglutide 0.3mg/day) and SGLT-2 inhibitor (canagliflozin 50mg/day). A 59-year-old man with advanced stage diabetic nephropathy (eGFR: 32.4mL/min/1.73m2; proteinuria: 8.90g/gCr), showing a rapidly progressive pattern (annual eGFR change: - 21.2mL/min/1.73m2/year), had an improvement in proteinuria (0.02g/gCr) and annual eGFR change (+ 0.1mL/min/1.73m2/year) after combination therapy with ARB (olmesartan 40mg/day), GLP-1 receptor agonist (liraglutide 0.9mg/day) and SGLT-2 inhibitor (tofogliflozin 10mg/day). These results suggest that this triple combination therapy has renoprotective effects on advanced stage rapidly progressive diabetic nephropathy.

Effects of Once-Weekly Dulaglutide on Glycemic Control and Renal Function in Patients with Advanced-Stage Diabetic Nephropathy

Objectives: Dulaglutide and liraglutide are glucagon-like peptide-1 receptor agonists. We investigated the effects of once-weekly dulaglutide on glycemic control and renal function compared to once-daily liraglutide in patients with advanced-stage diabetic nephropathy. Methods: Changes over a 12-month period in levels of glycated hemoglobin, urine protein/creatinine ratio, and annual change in estimated glomerular filtration rate were retrospectively analyzed in 10 patients with advanced-stage diabetic nephropathy after changing from once-daily liraglutide (0.9 mg/day) to once-weekly dulaglutide (0.75 mg/week) (dulaglutide group). The control group comprised 10 patients with advanced-stage diabetic nephropathy who had continued once-daily liraglutide (0.9 mg/day) (liraglutide group). Results: The glycated hemoglobin level significantly decreased in the dulaglutide group after switching from liraglutide to dulaglutide (-0.81 ± 1.03% at 12 months from baseline, P < 0.05), but no change occurred in the liraglutide group. The urine protein/creatinine ratio and annual change in estimated glomerular filtration rate did not change in either groups. Conclusions: Once-weekly dulaglutide may be more advantageous for glycemic control compared to once-daily liraglutide in patients with advanced-stage diabetic nephropathy.

Effects and Safety of Linagliptin as an Add-on Therapy in Advanced-Stage Diabetic Nephropathy Patients Taking Renin–Angiotensin–Aldosterone System Blockers

Abstract non disponibile

The Protective Effect Of A Low-protein Diet Against Tubulo-interstitial Damage In Diabetic Kidneys

Clinically, the efficacy of a low-protein diet (LPD) on diabetic nephropathy is controversial. Our study clearly showed that a very-low-protein diet (VLPD) intervention improved advanced diabetic nephropathy, particularly tubulo-interstitial injuries by restoring autophagy through the suppression of the mammalian target of rapamycin complex 1 (mTORC1) pathway, in a rat model of type 2 diabetes and obesity. Therefore, a VLPD should be expected as a clinically relevant means of suppressing the decline in renal function that occurs during advanced diabetic nephropathy. However, a severe pan-amino acid restriction should be avoided because of its resulting nutritional issues in patients. Further studies to elucidate which amino acids should be restricted for the greatest renoprotection are necessary for developing replacements for a VLPD to treat the advanced stages of diabetic nephropathy.

Effects and Safety of Linagliptin as an Add-on Therapy in Advanced-Stage Diabetic Nephropathy Patients Taking Renin-Angiotensin-Aldosterone System Blockers.

BACKGROUNDWe investigated the effects and safety of linagliptin as an add-on therapy in patients with advanced-stage diabetic nephropathy (DMN) taking renin–angiotensin–aldosterone system (RAAS) blockers.METHODTwenty advanced-stage DMN patients (estimated glomerular filtration rate (eGFR): 24.5 ± 13.4 mL/min/1.73 m2) taking RAAS blockers were administered 5 mg/day linagliptin for 52 weeks. Changes in glucose and lipid metabolism and renal function were evaluated.RESULTSLinagliptin decreased glycosylated hemoglobin levels (from 7.32 ± 0.77% to 6.85 ± 0.87%, P < 0.05) without changing fasting blood glucose levels, and significantly decreased total cholesterol levels (from 189.6 ± 49.0 to 170.2 ± 39.2 mg/dL, P < 0.05) and low-density lipoprotein cholesterol levels (from 107.1 ± 32.4 to 90.2 ± 31.0 mg/dL, P < 0.05) without changing high-density lipoprotein cholesterol and triglyceride levels. Urine protein/creatinine ratio and annual change in eGFR remained unchanged. No adverse effects were observed.CONCLUSIONLinagliptin as an add-on therapy had beneficial effects on glucose and lipid metabolism without impairment of renal function, and did not have any adverse effects in this population of patients with advanced-stage DMN taking RAAS blockers.

Antioxidant capacity and structural changes of human serum albumin from patients in advanced stages of diabetic nephropathy and the effect of the dialysis.

Changes in the antioxidant capacity of albumin and alterations of the albumin structural conformation were examined in patients in advanced stages of diabetes nephropathy. Human serum albumin was purified from diabetic patients in pre-dialysis (glomerular filtration rate [GFR] between 15 and 29 ml min(-1) 1.73 m(-2)) and those in dialysis (GFR ≤ 15 ml min(-1) 1.73 m(-2)) and then compared with albumin from patients with a normal GFR (>90 ml min(-1) m(-2)). We evaluated the antioxidant capacity of albumin using an enhanced chemiluminescence-based assay and thiol group content, and the structural changes were evaluated by circular dichroism and fluorescence spectroscopy. The antioxidant capacity and thiol content of albumin from patients in advanced stages of diabetic nephropathy were markedly reduced. The circular dichroism spectra showed a mean albumin α-helix content reduction from 44 to 37 % and from 44 to 30 % between the control group and pre-dialysis and dialysis patients, respectively. Additionally, the fluorescence intensity was reduced by 4.2 and 13 % for the groups 4 and 5, respectively, in relation with the control. These data provide evidence for the partial denaturation of albumin and exacerbated oxidative stress among patients in advanced stages of diabetes nephropathy before and even after dialysis.

Rodent animal models: from mild to advanced stages of diabetic nephropathy

Diabetic nephropathy (DN) is a secondary complication of both type 1 and type 2 diabetes, resulting from uncontrolled high blood sugar. 30–40 % of diabetic patients develop DN associated with a poor life expectancy and end-stage renal disease, causing serious socioeconomic problems. Although an exact pathogenesis of DN is still unknown, several factors such as hyperglycemia, hyperlipidemia, hypertension and proteinuria may contribute to the progression of renal damage in diabetic nephropathy. DN is confirmed by measuring blood urea nitrogen, serum creatinine, creatinine clearance and proteinuria. Clinical studies show that intensive control of hyperglycemia and blood pressure could successfully reduce proteinuria, which is the main sign of glomerular lesions in DN, and improve the renal prognosis in patients with DN. Diabetic rodent models have traditionally been used for doing research on pathogenesis and developing novel therapeutic strategies, but have limitations for translational research. Diabetes in animal models such as rodents are induced either spontaneously or by using chemical, surgical, genetic, or other techniques and depicts many clinical features or related phenotypes of the disease. This review discusses the merits and demerits of the models, which are used for many reasons in the research of diabetes and diabetic complications.

Abnormal lipoprotein metabolism in diabetic nephropathy

It is well known that patients with diabetes have a high incidence of cardiovascular disease (CVD), and the incidence of CVD becomes substantially elevated with development of diabetic nephropathy. The mechanisms for dyslipidemia in diabetic nephropathy are multifactorial and complex. Long-term hyperglycemia causes generalized vascular endothelial damage, which reduces functional lipoprotein lipase, leading to increased triglyceride (TG) levels and decreased high-density lipoprotein cholesterol (HDL-C). In overt-diabetic nephropathy, hypoproteinemia markedly increases low-density lipoprotein cholesterol (LDL-C), and renal failure specifically increases remnant lipoproteins and decreases HDL-C and LDL-C. Overt diabetic nephropathy exhibits remarkable postprandial hypertriglyceridemia with hyper-apolipoprotein (apo) B48, a marker of chylomicron and its remnants. Apo CIII is a key inhibitor of lipolysis and particle uptake of TG-rich lipoproteins, which is specifically increased in advanced chronic kidney disease, irrespective of the presence of diabetes. LDL size becomes smaller with advanced stages of diabetic nephropathy, whereas LDL size is not reduced in hemodialysis patients (HD). HD patients have marked lower levels of HDL3-C than controls. HD patients also have substantially low apo AI and high serum amyloid A (SAA) levels, suggesting the replacement of apo AI by SAA is stimulated in HDL particles.

Clinical relevance of visit-to-visit blood pressure variability: impact on renal outcomes

An impaired renal function has been found associated with very high cardiovascular (CV) risk, especially in subjects with type 2 diabetes. Microalbuminuria is a sensitive early marker of renal damage, often preceding the more advanced stages of diabetic nephropathy. Consistent evidence has been provided that any degree of quantifiable albuminuria, even in the range of normoalbuminuria, is a significant predictor of CV events and progression to end-stage renal disease. This is of particular relevance in subjects with type 2 diabetes in whom the prevalence of microalbuminuria may be as high as 50%. This has motivated the search for novel, yet modifiable risk factors the correction of which may contribute to prevention of albuminuria development and of renal impairment progression in patients with type 2 diabetes, aimed at further reducing the overall CV risk profile in these patients. One of these proposed novel risk factors is an increase in blood pressure variability (BPV). This suggestion is supported by a series of studies, carried out either in diabetic and in nondiabetic populations, which have provided evidence that an increased BPV, in addition to increased average BP levels, may be an independent predictor not only of CV events and mortality but also of development and progression of renal disease. The purpose of the present paper is to provide a critical review of the evidence exploring the relationship between BPV and renal dysfunction with particular emphasis on the relationship between visit-to-visit BPV and urinary albumin excretion variability.

Experimental diabetic nephropathy is accelerated in matrix metalloproteinase-2 knockout mice

Matrix metalloproteinase-2 (MMP-2) is responsible for the degradation of various types of extracellular matrix (ECM) proteins such as type IV collagen. Decreased MMP-2 expression and activity has been generally thought to contribute to increased accumulation of ECM at the advanced stage of diabetic nephropathy. However, the kinetics and role of MMP-2 in the early phase of diabetic nephropathy remain unclear. To address this issue, we examined whether streptozotocin (STZ)-induced early diabetic nephropathy was accelerated in MMP-2 knockout (KO) mice. Diabetes was induced by the injection of STZ in 6-week-old control and MMP-2 KO mice. Animals were killed after 16 weeks of diabetes of after observation alone. Compared with non-diabetic control mice, renal MMP-2 expression and activity were increased in 16-week old diabetic mice. Serum levels of blood urea nitrogen and creatinine and urinary excretion levels of albumin and N-acetyl-β-D-glucosaminidase were significantly elevated in diabetic MMP-2 KO mice when compared with wild-type diabetic littermates. Further, accumulation of ECM in the glomeruli and atrophy and fibrosis in the tubulointerstitium were exacerbated, and renal α-smooth muscle actin expression was enhanced in diabetic MMP-2 KO mice. Our present study suggests that renal expression and activity of MMP-2 are increased as a compensatory mechanism in the early phase of diabetic nephropathy. Since MMP-2 could play a protective role against the progression of diabetic nephropathy, further enhancement of MMP-2 expression and/or activity in the kidney may be a therapeutic target for the treatment of early diabetic nephropathy.

Detecção precoce da nefropatia diabética

Due to the unfavorable prognosis of advanced stages of diabetic nephropathy (DN), the ideal approach is to identify renal involvement as early as possible. It is recommended to measure urinary albumin excretion (UAE) annually, in random urine samples, in order to detect the stages of DN [microalbuminuria (UAE 17-174 mg/l or 30-300 mg albumin/g of creatinine) and macroalbuminuria (> 174 mg/l or > 300 mg/g)]. However, it has been suggested that UAE levels below the threshold of consensus could already signal the risk for DN progression and increased mortality, indicating the need to revise cutoff values. As a substantial amount of UAE (the immunounreactive fraction), is not detected by conventional methods, HPLC would be more sensitive to identify the presence of damage by measuring total UAE (immunoreactive + immunounreactive). Another recent observation is that diminished glomerular filtration rates (GFR) occurs in the presence of normoalbuminuria. Therefore, besides evaluating UAE, it is recommended to estimate GFR with equations employing creatinine; such as the Modification of Diet in Renal Disease (MDRD) study, available at www.mdrd.com. Owing to the known limitations of creatinine, alternative endogenous markers are being studied, and cystatin-C is a promising marker under investigation. Finally, new strategies that could detect DN even earlier, include biomarkers such as proteomics, defining a profile of urinary protein excretion able to identify the subsequent risk of renal disease.

Directional Power Doppler (dPd) in early ocular vs. renal vascular changes in diabetes mellitus type II

pDd identifies early hemodynamic abnormalities in diabetes. We evaluated renal and ocular hemodynamics in early to advanced stages of diabetic nephropathy. 131 diabetic patients (62±8 y) grouped according to kidney failure, were studied: D1 (8 ♂, 1 ♀): creatinine clearance (ClCr.) ≥90ml/min; D2 (23 ♂, 14 ♀): ClCr.=89–60; D3 (30 ♂, 14 ♀): ClCr=59–30; D4 (14 ♂, 5 ♀): ClCr.=29–15; D5 (17 ♂, 5 ♀):ClCr. <15. Controls (C, 16 ♂, 16 ♀) were also studied. pDd measured Resistance Index (RI) at renal interlobe level; eye study evaluated systolic peak speed and RI of retina central (RCA). In diabetics ocular RI was always increased compared to controls: C=0.61±0.04; D1=0.82±0.11 (p<0.05 vs. C); D2=0.78±0.12 (p<0.05 vs. C); D3=0.85±0.09 (p<0,05 vs. C, D2); D4 and D5=0.88±0.08 (p<0.05 vs. C, D2, D3). RI was not related to age, diabetes duration, BMI, blood pressure, renal volume, glomerular filtrate, proteinuria and glycemia in all groups. The RCA flow velocity resulted reduced in diabetic nephropathy since early stages: D1=10.5±2.1cm/s; D2=10.5±2.4; D3=11.7±3.4; D4=10.5±3.1; D5=9.9±2.6. Renal interlobe artery IR was near normal in D1 and D2 (0.68±0.07) and significantly increased in D3 (0.77±0.10), D4 (0.88±0.08) and D5 (0.94±0.06). Directional Power Doppler is capable to detect early ocular hemodynamic abnormalities in diabetic patients. Thus, dPd should be a useful tool to early identify diabetic nephtropathy.

Effect of MTHFR C677T genotype on survival in type 2 diabetes patients with end-stage diabetic nephropathy

The MTHFR C677T single nucleotide polymorphism TT genotype is associated with increased levels of plasma homocysteine and possibly an effect on cardiovascular mortality. We evaluated the effect of C677T genotype on mortality in a large end-stage renal disease (ESRD) cohort. C677T genotype was determined in 439 Caucasians with end-stage diabetic nephropathy (DNP) (cases) recruited from 30 dialysis centres in Southern Germany. A total of 482 type 2 diabetes patients without DNP (no microalbuminuria) at inclusion served as a genotype control collective. Patients were prospectively followed for 4 years. Primary endpoint was all-cause mortality. In contrast to controls, the genotype distribution in cases was not in Hardy-Weinberg equilibrium (HWE, P = 0.003), due to a less than expected number of patients with the TT genotype. The requirements of HWE were met in cases with < 2 years dialysis therapy prior to study inclusion (n = 219). TT genotype was associated with a decreased body mass index (P = 0.002) and long diabetes duration in dialysis patients (P = 0.03). However, TT genotype was not associated with an increased risk of all-cause or cardiac mortality in the total dialysis collective or the subgroup. Also, we observed no association of MTHFR genotype with cardiovascular morbidity in cases or controls (P > 0.05), or with an increased rate of progression to novel microalbuminuria. MTHFR 677TT genotype was significantly underrepresented in patients with ESRD in our study, but was not associated with premature mortality in these patients. We found no evidence for survival bias due to C677T genotype in the ESRD cohort, or bias due to genetically determined accelerated progression to novel microalbuminuria in the controls. However, we cannot exclude that the TT genotype protects from progression from microalbuminuria to more advanced stages of DNP, or that TT genotype is associated with premature mortality before a patient progresses to ESRD.